1. Field of the Invention
This invention relates to an apparatus for the production of musical tones, and in particular, it relates to instruments of the keyboard type, especially instruments in the nature of the acoustic (non-electrical) piano. Still more particularly, it has reference to the sounding board of such an instrument and the parts of the instrument which are adjacent thereto or in contact therewith. The invention is concerned with the objective of obtaining, especially from an instrument of relatively more modest size and cost, such as a spinet, the desirable tones, high in amplitude and with long decay-time characteristic, a characteristic that can also be enhanced in a far larger and most costly instrument, such as a concert grand piano.
2. Description of the Prior Art
Acoustic pianos are made, as is well known, in the a spectrum of styles or sizes, ranging from the lowly spinet through the console and the upright to baby grand and concert grand. They all operate on the same principles, creating musical tones of audible amplitude in desired frequencies (pitches) by providing a keyboard means which can be activated to cause a hammer means to strike, when a key is depressed, a vibrator means (a tuned string or strings), and when the key is released, to cause a damper means to come into contact with the vibrator means. The tuned strings are located in close proximity to a sounding board which is caused to resonate by the energy emitted from the vibrator means and thereby mechanically amplify and broadcast the tones emanating from the vibrator means.
Historically and extending to current times, piano sounding boards have been anchored to the piano harp and the perimeter of the piano case. Bridges (such as tenor, treble and bass) are attached to the sounding board, and the strings stretch over and bear down upon the bridges. The sounding boards are designed with a crown, convex in shape when viewed from the front of the piano, and in most cases, this crown is strengthened and maintained by means of ribs which are glued to the back of the sounding board to ensure that the crown will not flatten out. Maintenance of the crown is critically necessary, because if, as the piano ages, it loses its crown, the strings lose their initial and desirable high degree of downbearing upon their associated bridges, and as a result, the piano loses its "bark", producing a dull sound, rather than the bright and crisp sound that it had when new.
The desire to obtain a larger-piano sound out of a smaller piano has existed in the art for about two centuries, but in recent decades, the emphasis has largely been upon trying to achieve this by means of the various new electrical or electronic devices (microphones and other transducers, amplifier, and speakers) as they have been invented. An example of this approach is contained in my U.S. Pat. No. 3,407,694, issued Oct. 29, 1968. In the structure shown in the patent, there are two sounding boards, each of which possesses a free edge, but it evinces and suggests nothing of the concept of the present invention, wherein an effort is made to produce an instrument having a sounding board with at least one pair of opposed edges which are in major part unconfined and thus more readily excitable to a desirable greater amplitude, and to produce natural sounds free of distortions commonly introduced by an electro-mechanical transducer equipment.